Text widget: add the Add Media button and enable the `wpview` plugin to show embedded media previews in the editor.

Props westonruter, azaozz.
See #40854.

git-svn-id: https://develop.svn.wordpress.org/trunk@41344 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/js/editor.js

@@ -562,18 +562,42 @@ window.wp = window.wp || {};
 		// Add wrap and the Visual|Text tabs.
 		if ( settings.tinymce && settings.quicktags ) {
 			var $textarea = $( '#' + id );
+
 			var $wrap = $( '<div>' ).attr( {
 					'class': 'wp-core-ui wp-editor-wrap tmce-active',
 					id: 'wp-' + id + '-wrap'
 				} );
+
 			var $editorContainer = $( '<div class="wp-editor-container">' );
+
 			var $button = $( '<button>' ).attr( {
 					type: 'button',
 					'data-wp-editor-id': id
 				} );
 
+			var $editorTools = $( '<div class="wp-editor-tools">' );
+
+			if ( settings.mediaButtons ) {
+				var buttonText = 'Add Media';
+
+				if ( window._wpMediaViewsL10n && window._wpMediaViewsL10n.addMedia ) {
+					buttonText = window._wpMediaViewsL10n.addMedia;
+				}
+
+				var $addMediaButton = $( '<button type="button" class="button insert-media add_media">' );
+
+				$addMediaButton.append( '<span class="wp-media-buttons-icon"></span>' );
+				$addMediaButton.append( document.createTextNode( ' ' + buttonText ) );
+				$addMediaButton.data( 'editor', id );
+
+				$editorTools.append(
+					$( '<div class="wp-media-buttons">' )
+						.append( $addMediaButton )
+				);
+			}
+
 			$wrap.append(
-				$( '<div class="wp-editor-tools">' )
+				$editorTools
 					.append( $( '<div class="wp-editor-tabs">' )
 						.append( $button.clone().attr({
 							id: id + '-tmce',

src/wp-admin/js/widgets/text-widgets.js

@@ -230,7 +230,8 @@ wp.textWidgets = ( function( $ ) {
 				// The user has disabled TinyMCE.
 				if ( typeof window.tinymce === 'undefined' ) {
 					wp.editor.initialize( id, {
-						quicktags: true
+						quicktags: true,
+						mediaButtons: true
 					});
 
 					return;
@@ -242,11 +243,23 @@ wp.textWidgets = ( function( $ ) {
 					wp.editor.remove( id );
 				}
 
+				// Add or enable the `wpview` plugin.
+				$( document ).one( 'wp-before-tinymce-init.text-widget-init', function( event, init ) {
+					// If somebody has removed all plugins, they must have a good reason.
+					// Keep it that way.
+					if ( ! init.plugins ) {
+						return;
+					} else if ( ! /\bwpview\b/.test( init.plugins ) ) {
+						init.plugins += ',wpview';
+					}
+				} );
+
 				wp.editor.initialize( id, {
 					tinymce: {
 						wpautop: true
 					},
-					quicktags: true
+					quicktags: true,
+					mediaButtons: true
 				});
 
 				/**